U.S. patent application number 14/003595 was filed with the patent office on 2014-08-21 for device to assist the opening of a covering element pivotably mounted relative to an edge of a frame.
The applicant listed for this patent is Alexandre Piermee. Invention is credited to Alexandre Piermee.
Application Number | 20140230330 14/003595 |
Document ID | / |
Family ID | 45974382 |
Filed Date | 2014-08-21 |
United States Patent
Application |
20140230330 |
Kind Code |
A1 |
Piermee; Alexandre |
August 21, 2014 |
DEVICE TO ASSIST THE OPENING OF A COVERING ELEMENT PIVOTABLY
MOUNTED RELATIVE TO AN EDGE OF A FRAME
Abstract
The present invention relates to a device to assist the opening
of a covering element pivotably mounted relative to an edge of a
frame. According to the invention, the assistance cylinder (6)
includes a hollow shaft (7), a guide pin (10) inserted in the
hollow shaft (7) and comprising at the end thereof opposite the end
wall (8) of the hollow shaft (7) a yoke (11), a spring (13)
inserted in the hollow shaft (7) surrounding the guide pin (10) and
mounted pre-stressed when unloaded between the end wall (4) of the
hollow shaft (7) and the yoke (11) of the guide pin (10), and a
means (14) secured to the end of the guide pin (10) and engaging
with the end wall (8) of the hollow shaft (7) for keeping the
pre-stressed spring (13) in the released state thereof. The
invention is useful in the field of road systems.
Inventors: |
Piermee; Alexandre; (Prix
Les Mezieres, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Piermee; Alexandre |
Prix Les Mezieres |
|
FR |
|
|
Family ID: |
45974382 |
Appl. No.: |
14/003595 |
Filed: |
March 8, 2012 |
PCT Filed: |
March 8, 2012 |
PCT NO: |
PCT/FR2012/050490 |
371 Date: |
May 5, 2014 |
Current U.S.
Class: |
49/279 ;
49/386 |
Current CPC
Class: |
Y10T 16/53836 20150115;
E05Y 2201/474 20130101; E05Y 2201/686 20130101; E02D 29/1418
20130101; E05Y 2900/612 20130101; F16F 1/128 20130101; Y10T
16/53834 20150115; E05Y 2201/11 20130101; E05F 1/105 20130101; E05F
1/1058 20130101; E06B 5/01 20130101 |
Class at
Publication: |
49/279 ;
49/386 |
International
Class: |
E05F 1/10 20060101
E05F001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2011 |
FR |
11 51 944 |
Claims
1. A device for assisting the opening of a covering element (3),
such as a hatch, a plug or a lid, pivotally mounted relative to an
edge (2a) of a frame (2) between a lowered position for closing the
frame (2) and a raised position for opening the frame, comprising
at least a spring actuator (6) connected and jointed through its
ends respectively with the covering element (3) and with the edge
(2a) of the frame (2), characterized in that the actuator (6)
comprises a hollow shaft (7), an end wall (8) of which includes an
external yoke (9) connected and jointed with the covering element
(3) or with the edge (2a) of the frame (2), a guide pin (10)
accommodated in the hollow shaft (7) and connected at its end
opposite to the end wall (8) of the hollow shaft (7) to the edge
(2a) of the frame (2) or to the covering element (3) through a
jointing yoke (11), a spring (13) accommodated in the hollow shaft
(7) while surrounding the guide pin (10) and being pre-stressed in
the unloaded state all along the guide pin (10) between the end
wall (8) of the hollow shaft (7) and the yoke (11) of the guide pin
(10), a length portion (10a) of which protrudes from the hollow
shaft (7), when the covering element (3) occupies its raised
opening position on the one hand and compressed in the hollow shaft
(7) between the end wall (8) of the hollow shaft (7) and the yoke
(11) of the guide pin (10) when the covering element (3) occupies
its lowered closing position on the other hand, and a means (14)
secured to one of the ends of the guide pin (10) for retaining the
pre-stressed spring (13) in the unloaded state, and in that, during
the assisted opening of the covering element (3) by the spring
actuator (6), the compressed spring (13) is released in order to
cause guided sliding of the hollow shaft (7) by the guide pin
(10).
2. The assistance device according to claim 1, characterized in
that the jointing yoke (11) is secured to the end of the guide pin
(10) and the end wall (8) of the hollow shaft (7) includes an
orifice (16) for letting through the guide pin (10) upon pivoting
of the covering element (3) between its lowered closing and raised
opening positions, in that in the lowered position for closing the
covering element (3), the guide pin (10) protrudes from the hollow
shaft (7) through the orifice (16) over a portion (10b) of its
length and in that in the raised position for opening the covering
element, the means (14) for retaining the spring (13) secured to
the end of the guide pin (10) bears upon the end wall (8) of the
hollow shaft (7).
3. The assistance device according to claim 2, characterized in
that the means for retaining the spring (13) comprises a screw
(14), a nut (19) secured to the end of the guide pin (10) and in
which the screw (14) is anchored, and a washer (18) interposed
between the screw head (17) and the nut (19) and bearing upon the
end wall (8) of the hollow shaft (7) in the raised position of the
covering element (3).
4. The assistance device according to claim 1, characterized in
that the spring (13) is concentrically mounted to the guide pin
(10) and to the hollow shaft (7) while being in contact with the
peripheral internal face (7a) of the hollow shaft (7).
5. The assistance device according to claim 1, characterized in
that the axis (Y1Y'1) for jointing the yoke (9) of the hollow shaft
(7) with the covering element (3) and the axis (Y2Y'2) for jointing
the yoke (11) of the guide pin (10) with the edge (2a) of the frame
(2) are parallel to the jointing axis (XX') of the covering
element, the jointing axis (Y2Y'2) is located at a fixed distance
below the jointing axis (XX') and the distance separating both
jointing axes (Y1Y'1) and (Y2Y'2) gradually increases as the
covering element (3) pivots from its lowered closing position to
its raised opening position.
6. The assistance device according to claim 2, characterized in
that the jointing yoke (9) of the hollow shaft (7) is connected and
jointed to the covering element (3) via another yoke (20)
perpendicularly secured to the internal face of the covering
element (3) and the jointing yoke (11) of the guide pin (10) is
connected and jointed with the edge (2a) of the frame (2) via
another yoke (21) perpendicularly secured to a plate (22) itself
secured to the edge (2a) of the frame (2) while extending under the
frame (2) perpendicularly to the plane of this frame.
7. The assistance device according to claim 6, characterized in
that in the lowered position for closing the covering element (3),
the length portion (10a) of the guide pin (10) protrudes from the
hollow shaft (7) under the covering element (3).
8. The assistance device according to claim 1, characterized in
that the jointing yoke (9) and the end wall (8) of the hollow shaft
(7) are made as a single piece welded to the hollow shaft (7) and
the jointing yoke (11) of the guide pin (10) is fixed by welding to
the end of the latter.
9. The assistance device according to claim 1, characterized in
that the spring actuator (6) substantially extends into the middle
plane of the frame (2) perpendicular to the latter.
10. The assistance device according to claim 1, characterized in
that the frame (2) is rectangular and the covering element (3) is
included in the frame (2) in its lowered closing position.
11. A spring actuator (6) intended for assisting the opening of a
covering element (3), such as a hatch, a plug or a lid, pivotally
mounted relatively to an edge (2a) of a frame (2), characterized in
that it comprises a hollow shaft (7), an end wall (8) of which
includes an external yoke (9) intended to be connected and jointed
with the covering element (3) or with the edge (2a) of the frame
(2), a guide pin (10) accommodated in the hollow shaft (7) and
including at its end opposite to the end wall (8) of the hollow
shaft (7) a yoke (11) intended to be connected to the edge (2a) of
the frame (2) or to the covering element (3), a spring (13)
accommodated in the hollow shaft (7) while surrounding the guide
pin (10) and being mounted pre-stressed in the unloaded state all
along the guide pin (10) between the end wall (8) of the hollow
shaft (7) and the yoke (11) of the guide pin (10), a length portion
(10a) of which protrudes from the hollow shaft (7), and a means
secured to the end of the guide pin (10) close to the end wall (8)
of the hollow shaft (7) while bearing upon this wall for retaining
the pre-stressed spring (13) in the unloaded state.
12. The spring actuator according to claim 11, characterized in
that the means for retaining the spring (13) comprises a screw
(14), a nut (19) secured to the end of the guide pin (10) and in
which the screw (14) is anchored, and a washer (18) interposed
between the screw head (17) and the nut (19) and bearing upon the
end wall (8) of the hollow shaft (7).
13. The spring actuator according to claim 11, characterized in
that the spring (13) is concentrically mounted to the guide pin
(10) and to the hollow shaft (7) while being in contact with the
peripheral internal face (7a) of the hollow shaft (7).
14. The spring actuator according to claim 11, characterized in
that the end wall (8) of the hollow shaft (7) includes an orifice
(16) letting through the guide pin (10).
15. The spring actuator according to claim 10, characterized in
that the jointing yoke (9) and the end wall (8) of the hollow shaft
(7) are made in a single piece welded to the hollow shaft (7) and
the jointing yoke (11) of the guide pin (10) is fixed by welding to
the end of the latter.
16. Roadway equipment comprising a covering element (3) such as a
hatch, a plug or a lid, pivotally mounted relatively to an edge
(2a) of a frame (2) mounted and secured to the ground or to a
roadway, characterized in that it comprises a device for assisting
the opening of the covering element (3), as defined in claim 1.
Description
[0001] The present invention relates to a device to assist the
opening of a covering element, such as a hatch, a plug or a lid,
pivotally mounted relative to an edge of a frame between a lowered
position for closing the frame and a raised position for opening
this frame.
[0002] In particular, but in a non-limiting way, it applies to a
roadway device, the covering element of which occupying its raised
position clears the opening of the frame for accessing a manhole
for visiting or inspecting an underground network.
[0003] Such assistance devices are known, which comprise actuators
which are each interposed between the covering element and the edge
of the frame of a roadway device.
[0004] Each assistance actuator may be of the gas type or of a type
comprising two concentrically accommodated springs one inside the
other in the cylinder of the actuator while being mounted
pre-stressed when unloaded between an end wall of the cylinder and
a piston which is mounted and slideably guided in the cylinder, and
secured to the end of the actuator rod.
[0005] If such gas or spring actuators give satisfaction for
assisting the operator upon opening the covering element from its
frame closure position, they are relatively expensive and of
extremely complex structure especially as regards the spring
actuators. Further, the spring actuator also has the drawback of
not providing a large assisting amplitude upon pivoting the
covering element from its closing position to the position for
opening the frame.
[0006] The object of the invention is to overcome the above
drawbacks of known assistance devices.
[0007] For this purpose, according to the invention, the device to
assist the opening of a covering element such as a hatch, a plug or
a lid, pivotally mounted relative to an edge of the frame between a
lowered position for closing the frame and a raised position for
opening this frame, comprising at least one spring actuator
connected in a jointed or hinged way through its ends to the
covering element and to the edge of the frame respectively, is
characterized in that the actuator comprises a hollow shaft, one
end wall of which includes an external yoke connected in a jointed
way to the covering element or to the edge of the frame, a guide
pin or rod accommodated in the hollow shaft surrounding the guide
pin and connected at its opposite ends to the end wall of the
hollow shaft to the edge of the frame or to the covering element
through a jointed yoke, a spring accommodated in the hollow shaft
surrounding the guide pin and being pre-stressed in the unloaded
state between the end wall of the hollow shaft and the yoke of the
guide pin on the one hand, a length portion of which protrudes from
the hollow shafts, when the covering element occupies its raised
opening position and compressed in the hollow shaft between the end
wall of the hollow shaft and the yoke of the guide pin on the other
hand, when the covering element occupies its lowered closing
position, and a means secured to one of the ends of the guide pin
for retaining the pre-stressed spring in the unloaded state, and in
that, during the assisted opening of the covering element by the
spring actuator, the compressed spring is released for causing
guided sliding of the hollow shaft by the guide pin.
[0008] Preferably, the jointed yoke is secured to the end of the
guide pin and the end wall of the hollow shaft includes an orifice
for letting through the guide pin during the pivoting of the
covering element between its lowered closing position and its
raised opening position, and in the lowered closing position of the
covering element, the guide pin protrudes from the hollow shaft
through this orifice over a portion of its length whereas in the
raised position for opening the covering element, the means
retaining the spring secured to the end of the guide pin bears upon
the end wall of the hollow shaft.
[0009] Advantageously, the means for retaining the spring comprises
a screw, a nut secured to the end of the guide pin and in which the
screw is anchored, and a washer interposed between the screw head
and the nut and bearing upon the end wall of the hollow shaft in
the raised position of the covering element.
[0010] Advantageously, the spring is concentrically mounted to the
guide pin and to the hollow shaft while being in contact with the
peripheral internal face of the hollow shaft.
[0011] The axis for jointing the yoke of the hollow shaft with the
covering element and the axis for jointing the yoke of the guide
pin with the edge of the frame are parallel to the jointing axis of
the covering element, the jointing axis of the yoke of the guide
pin is located at a fixed distance below the jointing axis of the
covering element and the distance separating both jointing axes of
both hollow shafts gradually increases as the covering element
pivots from its lowered closing position to its raised opening
position.
[0012] Preferably, the jointing yoke of the hollow shaft is
connected through a joint to the covering element via another yoke
secured perpendicularly to the internal face of the covering
element and the jointing yoke of the guide pin is connected through
a joint to the edge of the frame via another yoke secured
perpendicularly to a plate itself secured to the edge of the frame
while extending under the yoke perpendicularly to the plane of the
latter.
[0013] In the lowered closing position of the covering element, the
length portion of the guide pin protrudes from the hollow shaft
under the covering element.
[0014] Advantageously, the jointing yoke and the end wall of the
hollow shaft are made in a single piece welded to the hollow shaft
and the jointing yoke of the guide pin is attached by welding to
the end of the latter.
[0015] The spring actuator substantially extends in the middle
plane of the frame perpendicular to the latter.
[0016] The frame is rectangular and the covering element fits into
the frame at its lowered closing position.
[0017] The invention is also directed to a spring actuator intended
for assisting the opening of a covering element, such as a hatch, a
plug or a lid, pivotally mounted relatively to an edge of the frame
and characterized in that it comprises a hollow shaft, an end wall
of which includes an external yoke intended to be connected through
a joint to the covering element or to the edge of the frame, a
guide pin accommodated in the hollow shaft and including at its end
opposite to the end of wall of the hollow shaft a yoke intended to
be connected to the edge of the frame or to the covering element, a
spring accommodated in the hollow shaft surrounding the guide pin
and being mounted pre-stressed in the unloaded state between the
end wall of the hollow shaft and the yoke of the guide pin, a
portion of the length of which protrudes from the hollow shaft, and
a means secured to the end of the guide pin close to the end wall
of the hollow shaft while bearing upon this wall in order to retain
the pre-stressed spring in the unloaded state.
[0018] Advantageously, the means for retaining the spring comprises
a screw, a nut secured to the end of the guide pin and in which the
screw is anchored, and a washer interposed between the screw head
and the nut and bearing upon the end wall of the hollow shaft.
[0019] The spring is concentrically mounted to the guide pin and to
the hollow shaft while being in contact with the peripheral
internal face of the hollow shaft.
[0020] The end wall of the hollow shaft includes an orifice for
letting through the guide pin.
[0021] The jointing yoke and the end wall of the hollow shaft are
made in a single piece welded to the hollow shaft and the jointing
yoke of the guide pin is attached by welding to the end of the
latter.
[0022] The invention is finally directed to a piece of roadway
equipment comprising a covering element, such as a hatch, a plug or
a lid, pivotally mounted relatively to an edge of a frame, and
which is characterized in that it comprises a device to assist the
opening of the covering element, as defined earlier.
[0023] The invention will be better understood, and other objects,
features, details and advantages thereof will become more clearly
apparent in the explanatory description which follows made with
reference to the appended drawings, only given as an example
illustrating two embodiments of the invention and wherein:
[0024] FIG. 1 is a perspective view of an assembly with a covering
element, a frame for supporting this element and an assistance
actuator according to a preferred embodiment of the invention, the
covering element occupying its raised position for opening the
frame;
[0025] FIG. 2 is a side view along the arrow II of FIG. 1 and
showing the assistance actuator in its position corresponding to
the lowered position for closing the covering element;
[0026] FIG. 3 is a side view similar to the one of FIG. 2 and
illustrating the assistance actuator in its position corresponding
to an intermediate opening position of the covering element;
[0027] FIG. 4 is an enlarged perspective view of FIG. 3;
[0028] FIG. 5 is a perspective view of the assistance spring
actuator in the assembled position, the spring of this actuator
being unloaded;
[0029] FIG. 6 is an exploded perspective view of the assistance
spring actuator of FIG. 5;
[0030] FIG. 7 is a side view along the arrow VII of FIG. 5;
[0031] FIG. 8 is a sectional view along the line VIII-VIII of FIG.
7;
[0032] FIG. 9 is a side view similar to the one of FIG. 7 and
illustrating the spring of the assistance actuator in the
completely compressed state;
[0033] FIG. 10 is a sectional view along the line X-X of FIG. 9;
and
[0034] FIG. 11 is a view illustrating another embodiment of the
assistance spring actuator of the invention.
[0035] Referring to FIGS. 1 to 10, reference 1 designates a roadway
device, which comprises a frame 2 secured to the ground or to a
roadway and a covering element 3 such as a hatch, a plug, a lid or
the like.
[0036] In the present case, the frame 2 is of a rectangular shape
and the covering element 3 also with a rectangular shape, is
mounted jointed along one 2a of the edges or sides of the frame 2
around a pivot axis XX' for allowing the covering element 3 to
pivot between a lowered position for closing the opening O of the
frame 2, in which the covering element 3 fits into the frame 2, and
a raised or standing opening position allowing the opening of the
frame 2 to be cleared in order to access a manhole for visiting or
inspecting an underground network.
[0037] As an example, the covering element is plate-shaped and,
like the frame 2, may be made in metal, such as steel.
[0038] FIG. 1 illustrates the raised position for opening the
covering element 3 which extends substantially perpendicularly to
the plane of the frame 2 passing through the sides of the latter
and FIG. 2 illustrates the covering element 3 in its lowered
position for closing the frame 2. In this latter position, the
covering element 3 bears upon a supporting internal peripheral wall
4 of the frame 2.
[0039] Locking means, not shown, are provided for locking the
covering element 3 to the frame 2 in its lowered closing position
in this frame. These locking means may comprise a bolt lock secured
to the covering element 3 in the vicinity of its edge opposite to
the jointing axis XX' in proximity to the location symbolized in
FIG. 1 by two drill holes 5 and a striker secured to the edge or
side 2b of the frame 2 opposite to the side 2a. Such a lock is
lockable or unlockable by means of a suitable wrench in order to
engage the bolt of the lock into the striker of the frame 2 or
disengage it from this striker. The drill holes 5 give the
possibility of letting through an end hook of a bar for lifting the
covering element 3 in order to bring it into its opening
position.
[0040] The roadway device 1 is equipped with a spring actuator 6
interposed between the covering element 3 and the frame 2 and
providing assistance to an operator for pivoting the covering
element 3 from its lowered position for closing the frame 2 to its
raised position for opening this frame.
[0041] According to the preferred embodiment of FIGS. 1 to 10, the
spring actuator 6 comprises a cylindrical hollow shaft 7, one end
of which is closed by a wall 8 from which two rigid parallel
branches 9a forming a yoke connected through a joint to the
internal face of the covering element 3 protrude exteriorly and
perpendicularly. Preferably, the wall 8 and the branches 9a of the
yoke 9 are made in a single piece which is attached to the end of
the hollow shaft 7 of the actuator 6 by welding.
[0042] The assistance actuator 6 further comprises an interiorly
hollow cylindrical rigid pin 10 accommodated in the hollow shaft 7
and which includes at its end opposite to the end wall 8 of the
hollow shaft 7 and outside the latter a yoke 11 with two parallel
rigid branches 11a secured to a plate 12 exteriorly and
perpendicularly to the latter and which is attached, for example by
welding, to the end of the pin 10. The plate 12 is positioned
perpendicularly to the pin 10.
[0043] The actuator 6 also comprises a spring 13, of the
compression coil type, accommodated in the hollow shaft 7
surrounding the pin 10 and being mounted pre-stressed in the
unloaded state, not compressed, as notably illustrated in FIGS. 5,
7 and 8, between the end wall 8 of the hollow shaft 7 and the wall
12 of the yoke 11 of the pin 10. Thus, in the unloaded state, the
spring 13 extends all along the pin 10 and includes an external
portion 13a surrounding the corresponding external pin portion 10a
of the pin 10 protruding from the hollow shaft 7.
[0044] The spring 13 is concentrically mounted to the pin 10 and to
the hollow shaft 7 and has its external perimeter in contact with
the peripheral internal face 7a of the hollow shaft 7. In the
unloaded state, the spring 13 is maintained pre-stressed between
the end wall 8 of the hollow shaft 7 and the plate 12 of the pin 10
by a means preferably comprising a screw 14, the threaded portion
15 of which is anchored to the end of the pin 10 coaxially and
which crosses an orifice 16 of the plate 8 coaxial with the hollow
shaft 7, the head 17 of the screw 14 bearing upon the wall 8 via a
washer 18.
[0045] The end of the pin 10 includes, welded to the latter, a nut
19 through which the screw 14 is screwed, the threaded portion 15
crossing the nut 19 engaging into the tubular end portion of the
pin 10. Thus, the washer 18 is confined between the head 17 and the
screw 14 and the nut 19. This assembly of the screw 14, washer 18
and nut 19 ensures adjustment of the pre-stress of the spring 13 in
its unloaded state between the wall 8 and the plate 12 in order to
avoid in this state any play in the longitudinal displacement of
the spring 13 along the pin 10.
[0046] The pin 10 may partly cross the orifice 16 of the wall 8 of
the hollow shaft 7 as this will be seen subsequently.
[0047] The jointing yoke 9 of the hollow shaft 7 is connected to
the covering element 3 via two rigid parallel tabs 20 secured to
the internal face of the covering element 3 perpendicularly to the
latter, both tabs 20 thus forming a jointing yoke. More
specifically, both branches 9a of the yoke 9 are positioned with
small play between both tabs 20 in the vicinity of the ends of the
latter and are jointedly mounted to these ends along a jointing
axis Y1Y'1 parallel to the covering element 3 or to the axis
XX.
[0048] The jointing of the yoke 9 to both tabs 20 is formed by two
cylindrical jointing axes, not shown, extending along the axis
Y1Y'1, each engaged through both coaxial drill holes 9b, 20b of a
branch 9a of the yoke 9 and of a corresponding tab 20, so that such
a joint cannot interfere with the passing of a portion of the pin
10 through the orifice 16 and through both branches 9a of the yoke
9.
[0049] Both branches 11a of the yoke 11 of the pin 10 are
positioned with small play between two parallel rigid tabs 21
themselves forming a yoke and which are secured perpendicularly to
the latter, to a plate 22 with the shape of a rigid plate itself
secured to the portion of the supporting wall 4 of the frame 2
perpendicularly to the latter, i.e. perpendicularly to the plane of
the frame 2 containing its four sides. The plate 22 extends under
the supporting wall portion 4 of the frame 2 and the two tabs 21
are secured together in the vicinity of the lower edge of this
plate.
[0050] The yoke 11 is jointed between both tabs 21 along a jointing
axis Y2Y'2 parallel to the jointing axis Y1Y'1 of the yoke 9 of the
hollow shaft 7. The jointing of the yoke 11 to the tabs 21 is
formed by two cylindrical axes, not shown, extending along the axis
Y2Y'2 and each inserted into the two coaxial drill holes 11b of a
branch 11a of the yoke 11 and 21b of the corresponding tab 21.
[0051] The branches 9a of the yoke 9 of the hollow shaft 7 and the
branches 11b of the yoke 11 of the pin 10 are positioned
symmetrically with the longitudinal middle plane of the actuator 6
and in the assembled position of the actuator 6 between the frame 2
and the covering element 3, the actuator 6 is positioned in the
middle plane of the frame 2 extending perpendicularly to the
latter.
[0052] When the covering element 3 occupies its lowered position
for closing the opening O of the frame 2, the spring 13 is
practically completely compressed in the hollow shaft 7 between the
end wall 8 of this hollow shaft and the plate 12 of the pin 10
which is found in the vicinity of the end of the hollow shaft 7
opposite to the end plate 8 as this notably emerges from FIGS. 2
and 10. FIG. 2 also shows that a length portion 10b of the pin 10
protrudes from the hollow shaft 7 through the orifice 16 of the
latter and between both branches 9a of the yoke 9 with the end 10b
including the screw 14, washer 18 and nut 19 assembly located below
the covering element 3 in the vicinity of its edge opposite to the
jointing axis XX'.
[0053] This figure also shows that the actuator 6, located largely
under the frame 2, is tilted relatively to the horizontal according
to a relatively small angle .alpha., for example of about
15.degree..
[0054] When an operator wishes to swing the covering element from
its lowered position for closing the opening O of the frame 2 to
its raised position for opening the frame 2, he/she first of all
actuates the lock for locking the covering element to the frame 2
in order to unlock it.
[0055] Next, he/she introduces into the drill holes 5 of the
covering elements 3 the end hook of a bar, in order to lift up this
element and the spring 13 then exerts, upon beginning its release,
a force along the longitudinal direction of the actuator 6 from the
fixed jointing yoke with an arm 21 of the plate 22 providing
assistance to the operator for opening the covering element 3. As
the operator gradually pivots the covering element 3 around the
axis XX' towards its raised opening position, the spring 13
continuously loses its tension so as to cause sliding of the hollow
shaft 7 guided by the pin 10 for exerting a force component
perpendicular to the covering element 3 giving the possibility of
assisting the pivoting of the covering element 3 around the axis
X-X'. FIG. 3 illustrates the covering element 3 in an intermediate
swinging position towards its raised opening position and shows
that the actuator 6 pivots around the axis Y2Y'2 and that during
this pivoting, the portion 10b of the guide tube 10, because of the
sliding of the hollow shaft 7, returns to the inside of the latter
with the portion 10a protruding out of the hollow shaft 7 with the
corresponding portion 13a of the spring 13, the end turns of which
are constantly maintained pressed, between the end wall 8 of the
yoke 7 and the end wall 12 of the pin 10.
[0056] The fixed distance a of the axis Y1Y'1 relatively to the
covering element 3 defined by the length of the tabs 20 and the
fixed distance b of this axis relatively to the axis XX' determined
by the location of the tabs 20 on the covering element 3, the fixed
height c of the axis Y2Y'2 relatively to the axis XX' determined by
the height of the plate 22 and the fixed distance d of the axis
Y2Y'2 relatively to the axis XX' in a direction parallel to the
plane of the frame 2 as well as the length of the spring 13 in the
unloaded state, are such that the actuator 6 constantly assists the
pivoting of the covering element 3 from its position for closing
the opening O of the frame 2 to its raised opening position with an
increase in the distance e separating both axes Y2Y'2 during this
pivoting and resulting from the displacement of the hollow shaft 7
guided by the pin 10. It should also be noted that the distance b
separating the axis Y1Y'1 from the axis XX' is greater than half
the length of the recovering element 3 from the axis XX'. In the
raised position for opening the covering element 3, the spring 13
is completely unloaded and slightly pre-stressed between the end
wall 8 of the hollow shaft 7 and the end plate 12 of the pin 10,
ensuring that the covering element 3 is maintained in this raised
position. The swinging of the covering element 3 beyond its raised
position of FIG. 1 is prevented by the yoke 11 which is bearing
upon the plate 22.
[0057] The design of the assistance actuator 6 gives the
possibility of using a spring with a very great length since it
extends from the end wall 8 of the hollow shaft 7 to the end wall
12 of the pin 10, ensuring quasi complete assistance with the
opening of the covering element 3.
[0058] As an example, the operator maneuvering the covering element
3 towards its opening position, because of the assistance of the
spring actuator 6, will exert a force of less than 250 Newtons.
[0059] The described preferred embodiment above of the assistance
actuator 6 allows it to be mounted between the covering element 3
and the plate 22 of the frame 2 while being not very cumbersome
under the frame 2 when the covering element 3 occupies its lowered
position for closing the opening O of this frame. Further, the
actuator 6 is of extremely simple and inexpensive design while
being efficient for ensuring its assistance function over the whole
swinging amplitude of the covering element 3 by exerting a force
allowing compensation of the weight of the covering element 3.
[0060] Further, the spring actuator 6 also ensures a damping
function when swinging the recovering element 3 from its raised
opening position to its closing position of the frame 2.
[0061] It should also be noted that after unlocking the lock of the
covering element 3 occupying its position for closing the frame 2,
the spring 13 may be tared for exerting a force causing slight
pivoting of the covering element 3 to a half-open position of its
edge opposite to the jointing axis XX' in order to allow the
operator to more easily grip the covering element 3 and to have it
swing with assistance from the actuator 6 towards its raised
opening position.
[0062] According to an alternative embodiment not shown, the
mounting of the assistance actuator 6 may be reversed, i.e. the
yoke 9 of the end wall 8 of the hollow shaft 7 would be mounted
between both tabs 21 of the plate 22 and the end yoke 11 of the pin
10 would be mounted and jointed between both tabs 20 of the
covering element 3. In this case, when the covering element 3 will
occupy its position for closing the frame 2, the portion 10b of the
pin 2 will obliquely protrude according to the same angle .alpha.
as in FIG. 2 beyond the plate 22 which will be cut out for this
purpose in order to let through the portion 10b of this pin. The
drawback of such an assembly is that it is necessary to dig a
chimney or underground tunnel of a larger width in order to receive
the portion 10b of the pin 10 in the closing position of the
covering element 3.
[0063] FIG. 11 illustrates another embodiment of the assistance
actuator 6.
[0064] According to this embodiment, the guide pin 10 for sliding
the hollow shaft 7 has its upper end secured to the end plate 8 of
the hollow shaft 7, for example by welding, the branches 9a of the
yoke 9 of the hollow shaft 7 being mounted and jointed along the
axis Y1Y'1 between both tabs 20 as in the first preferred
embodiment.
[0065] Further, the yoke 11, which is also mounted and jointed
along the axis Y2Y2' between both tabs 21 of the plate 22, like in
the first preferred embodiment, is secured to the plate 12 which
includes a central orifice 12a for letting through a portion of the
guide pin 10.
[0066] The free end of the guide pin 10 opposite to the end wall 8
of the hollow shaft 7 includes the same screw 14, washer 18 and nut
19 assembly as the one of the first preferred embodiment and it
will therefore not be again detailed except that it ensures the
function for retaining the spring 13 in the unloaded state slightly
pre-stressed between the plate 12 and the end wall 8 of the hollow
shaft 7.
[0067] When the covering element 3 occupies its position for
closing the frame 2 illustrated in FIG. 2, the spring 13 is
practically completely compressed between the end wall 8 of the
hollow shaft 7 and the plate 12 of the yoke 11 and a portion 10b of
the guide pin 10 protrudes through the orifice 12a beyond the
plate, not shown, according to an angle identical with the angle
.alpha. of FIG. 2, as illustrated in dotted lines in FIG. 11.
[0068] The operation of the actuator 6 for assisting the operator
with the opening of the covering element 3 towards its raised
position is similar to the one of the assistance actuator 6 of the
first preferred embodiment and will therefore not be detailed again
except that the gradual release of the spring during the pivoting
of the covering element 3 towards its raised position for the
opening causes guided sliding of the hollow shaft 7 with the pin 10
for exerting the force assisting the covering element until the
latter occupies its corresponding raised position at the position
of the actuator 6 as illustrated in solid lines in FIG. 11.
[0069] Of course, the plate 22 will be cut out at its lower portion
in order to let through the pin portion 10b to the closing position
of the covering element 3 in the frame 2.
[0070] The drawback of this second embodiment is that it is
necessary to make a chimney of larger width contrary to the first
preferred embodiment.
[0071] Various embodiment alternatives may be provided without
departing from the scope of the present invention.
[0072] Thus, it is possible to provide two side assistance
actuators 6, each being preferably identical with the one of the
first embodiment.
[0073] Further, the frame 2 may have a shape other than a
rectangular shape, for example a circular shape.
[0074] The assistance actuator of the invention described above
thus allows for a spring of very great length with which it is
possible to obtain a very large amplitude assisting the actuator
upon opening the covering element with which it is associated.
Further, the assistance actuator of the invention is of an
extremely simple structure making its manufacturing and its
mounting more rapid and is less expensive than gas actuators and
dual spring actuators which have been used up to now.
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